Electric lifting desks are generally used in homes or offices. When a user adjusts the height, if there is an obstacle, damage may be caused to the obstacle or the structure of a lifting desk. If the human body is collided, personal injury may be caused. In order to improve the product safety, the lifting desk product in the prior art may be additionally provided with a function of stopping or retreating in case of an obstacle.
Most of the lifting desk products on the market achieve the function of stopping or retreating in case of an obstacle by the following approaches: 1. whether an obstacle is encountered is judged by checking for an abrupt change in current during collision; 2. an obstacle is detected by a mechanical sensor such as a piezoelectric sensor or a spring; and 3. a three-axis acceleration sensor is used to detect whether the lifting desk has a rising obstacle to judge whether an obstacle is encountered. Abrupt current change detection is generally used for fixed obstacle detection, but has low sensitivity for the detection of resistance with a smaller force, for example, when a user presses a desktop and if only the magnitude of a current value is judged, the current value is not accurately judged due to different service conditions under different working conditions. Mechanical sensors have high mounting requirements and are not easy to produce. Three-axis acceleration sensors have high cost and tend to misjudgment.